Wisconsin agriculture officials say emerald ash borers have been found at Mirror Lake State Park.
The discovery has prompted agriculture officials to quarantine Sauk County for the invasive pest.
A number of the adult beetles were caught in one of the purple traps set out around Wisconsin to monitor for emerald ash borers.
In addition, Wisconsin Department of Natural Resources forest health staff found immature beetles and other signs of infestation when they peeled bark from some of the ash trees at the park entrance.
U.S. Department of Agriculture officials confirmed the beetles are emerald ash borers.
The quarantine will apply to all of Sauk County. It prohibits wood products from being moved out of the county to areas that are not infested.